基于改进离散粒子群算法的传感器优化配置

传感器优化配置是实现航空设备故障预测与健康管理(Prognostics and Health Management,PHM)系统设计的基础和保证.本文首先对系统的故障-传感器相关性矩阵进行了改进,在此基础上根据系统测试性指标要求建立了考虑传感器故障率的约束优化模型,并采用一种改进的离散粒子群算法求解.算法根据传感器优化配置的特点设计了粒子个体适应度计算方法,惯性权重则基于群体早熟程度自适应调整.仿真实例验证了本文方法的有效性,优化结果满足系统各项测试性指标要求,可为航空设备PHM系统的传感器优化配置提供有效指导.     

Dynamic theoretic proactive caching placement game for energy saving in H‐CRAN

Edge caching is an effective feature of the next 5G network to guarantee the availability of the service content and a reduced time response for the user. However, the placement of the cache content remains an issue to fully take advantage of edge caching. In this paper, we address the proactive caching problem in Heterogeneous Cloud Radio Access Network (H‐CRAN) from a game theoretic point of view. The problem is formulated as a bargaining game where the remote radio heads (RRHs) dynamically negotiate and decide which content to cache in which RRH under energy saving and cache capacity constraints. The Pareto optimal equilibrium is proved for the cooperative game by the iterative Nash bargaining algorithm. We compare between cooperative and noncooperative proactive caching games and demonstrate how the selfishness of different players can affect the overall system performance. We also showed that our cooperative proactive caching game improves the energy consumption of 40% as compared with noncooperative game and of 68% to no‐game strategy. Moreover, the number of satisfied requests at the RRHs with the proposed cooperative proactive caching scheme is significantly increased.     

深亚微米SOI工艺SoC设计中天线效应的消除

深亚微米SOI片上系统芯片(SoC)因其工艺特性,按照常规的布局布线(PNR)流程,出现了约一万个天线效应违规。介绍了一种在布局布线阶段不插入反偏二极管就可以消除大量天线效应违规的优化迭代流程。通过对天线效应的产生以及天线比率公式的分析,从线长和栅面积角度考虑天线效应的修复,结合自动布局布线设计工具SoC Encounter对这些因素的控制,可以在布局布线阶段消除天线效应的违规,并能与版图验证的结果保持一致。在一款通用抗辐照SoC芯片的设计中,应用该优化流程在布局布线阶段消除了设计中的天线效应违规,有效节约了芯片整体设计时间。     

动态环境下MIMO 雷达站点优化配置方法

针对动态环境下多监视区域的分布式多输入多输出(MIMO)雷达站点优化配置问题,提出基于卡尔曼滤波(KF)与粒子群优化(PSO)的站点配置方法。文中考虑MIMO 雷达系统要实时监视多区域,并根据环境的变化计算不同时刻的站点最优配置方案,建立了待优化数学模型,给出了算法的求解过程及步骤,最后通过仿真验证了算法在动态环境下的有效性,可显著提升各个时刻雷达站点最优配置方案的计算效率,并改善最优配置方案的性能。     

分布式声源定位系统节点最优布局方法及性能研究

为提高基于到达时间TOA（Time of Arrival）的分布式声源定位系统在应用中的定位精度,推导出各节点测量性能存在差异条件下定位误差的CRLB（Cramer Rao Lower Bound）,遵循探测区域定位误差的平均CRLB最小的最优准则,对目标以均匀分布和高斯分布概率出现的情形,采用自适应遗传算法进行最优布局仿真研究.仿真结果表明,基于节点观测性能的最优布局与声源出现的概率分布直接相关;且与不考虑节点性能时的最优布局相比,提高了定位区域的整体定位精度.     

大学化学先修课程的实践与思考

中国大学先修课程是国内在基础教育阶段探索人才培养的一种新模式,同时也是高校探索通过综合评价选拔人才的途径之一。在连续3个轮次教学实践的基础上,北京师范大学第二附属中学对大学化学课程的目标定位、课程内容、实施方式以及资源建设等方面进行了系统的总结,讨论了目前大学先修课程实施过程中所面临的若干问题。     

Accelerating molecular modeling applications with graphics processors

Molecular mechanics simulations offer a computational approach to study the behavior of biomolecules at atomic detail, but such simulations are limited in size and timescale by the available computing resources. State-of-the-art graphics processing units (GPUs) can perform over 500 billion arithmetic operations per second, a tremendous computational resource that can now be utilized for general purpose computing as a result of recent advances in GPU hardware and software architecture. In this article, an overview of recent advances in programmable GPUs is presented, with an emphasis on their application to molecular mechanics simulations and the programming techniques required to obtain optimal performance in these cases. We demonstrate the use of GPUs for the calculation of long-range electrostatics and nonbonded forces for molecular dynamics simulations, where GPU-based calculations are typically 10-100 times faster than heavily optimized CPU-based implementations. The application of GPU acceleration to biomolecular simulation is also demonstrated through the use of GPU-accelerated Coulomb-based ion placement and calculation of time-averaged potentials from molecular dynamics trajectories. A novel approximation to Coulomb potential calculation, the multilevel summation method, is introduced and compared with direct Coulomb summation. In light of the performance obtained for this set of calculations, future applications of graphics processors to molecular dynamics simulations are discussed.     

遗传算法应用于VLSI布局的研究

本文是应用遗传算法实现ＶＬＳ门阵列模式布局,从建立相应的数学模型入手,提出一个较完备的综合布局目标函数,引入通道拥挤度的概念,从而改变了传统的常以总线长度或刻线数目的单一目标函数,使布局的构形更趋合理。在遗传３参数选取方面,提出了几种改善收性的措施,大大加快了遗传算法的收敛速度。     

ASIC后端设计中的时钟树综合

时钟树综合是当今集成电路设计中的重要环节,因此在FFT处理器芯片的版图设计过程中,为了达到良好的布局效果,采用时序驱动布局,同时限制了布局密度;为了使时钟偏移尽可能少,采用了时钟树自动综合和手动修改相结合的优化方法,并提出了关于时钟树约束文件的设置、buffer的选型及手动修改时钟树的策略,最终完成了FFT处理器芯片的时钟树综合并满足了设计要求。     

Facility placement with sub-aisle design in an existing layout

In this paper, we consider the integration of facility placement in an existing layout and the configuration of one or two connecting sub-aisles. This is relevant, for example, when placing a new machine/department on a shop floor with existing machines/departments and an existing aisle structure. Our work is motivated by the work of Savas et al. [Savas, S., Batta, R., Nagi, R., 2002. Finite-size facility placement in the presence of barriers to rectilinear travel. Operations Research 50 (6), 1018–1031], that considered the optimal planar placement of a finite-size facility in the presence of existing facilities. Our work differs from theirs in that we consider material handling to be restricted to the aisle structure. We do not allow the newly placed facility to overlap with existing facilities or with the aisle structure. Facilities are rectangular and travel is limited to new or existing aisles. We show that there are a finite number of candidate placements for the new facility. Algorithms are developed to find the optimal placement and the corresponding configurations for the sub-aisles. Complexity of the solution method is analyzed. Also, a numerical example is provided to explore the impact of the number of sub-aisles added.